Background: Patient disengagement from HIV care and treatment programs is a major barrier to treatment optimization in sub-Saharan Africa. While initial studies show that patient re-engagement in care is possible, very little is known about re-engagement patterns, associated factors and how they lead to return to care. Study Objective: The goal of this study is to understand the patterns, predictors and mechanisms of re- engagement in HIV care among adult HIV patients in Zambia in order to inform interventions to support return and subsequent retention. Specific Aims: I. Among a representative, longitudinal cohort of disengaged patients in Zambia, identify time to return and individual (e.g. demographics), relational (e.g. disclosure), household (e.g. wealth), and facility-level (e.g. staffing) factors that predict return to HIV care, comparing disengaged patients who re-engaged in HIV care to those who did not re-engage after being traced. II. Develop a refined conceptual model of the mechanisms of patient re-engagement to guide patient re-engagement support interventions. Approach: The sequential, mixed methods study builds on the applicant?s significant past experience living and contributing to research in Zambia. It leverages the data and infrastructure of an on-going parent study on which the applicant is a co-investigator. The parent study is tracing 5,000 randomly sampled, lost adult HIV patients from 31 health facilities across 4 provinces in Zambia to determine their outcomes: deceased, engaged in care elsewhere or disengaged from care. Aim 1 will be a secondary data analysis of the estimated 1,000 disengaged patients from the parent study, among whom an estimated 25% (n=250) will re-engage in care over 15 months. Survival analysis will be used to estimate time to return and identify multi-level predictors of return across a social ecological framework. Sub-Aim 1a will examine the impact of tracing (peer educator outreach to lost patients) on return. Aim 2 will collect in-depth interview data from disengaged patients who returned to HIV care. Drawing on the factors identified in Aim 1 and grounded theory to allow other factors to emerge, Aim 2 seeks to explain the mechanisms through which factors associated with re-engagement operate. Final results will be triangulated to develop a refined conceptual model of HIV care re-engagement that can guide the design and testing of interventions to facilitate return. Fellowship Information: The proposed research will serve as the doctoral dissertation of Ms. Laura Beres, a current PhD student in the Department of International Health at Johns Hopkins University. The training is guided by one Sponsor, two Co-sponsors and a Scientific Advisor who offer complementary expertise in HIV and analytic skills required for the study. Training includes coursework, field research and other opportunities to prepare Ms. Beres to become a leading independent researcher in global HIV prevention and care.